Electric motor or generator.



H.-A. BAL COME. ELECTRIC MOTOR 0R GENERATOR.

A-PPLIOATION FILED NOV.17,11910.

Patented se t. 26,1911.

.- UNIT s'rA'rris PATENT OFFICE.

nnnnnn'r A. sarcoma, or nosron, massncnosnr'rs, nssrenon TO THEnon'rznacarom nm'c'rmc mssacnusn'r'rs.

COMPANY, or nnooxmnn,

Specification of Letters Patent. Application flied November 17, 1910.Serial No. 592,832.

MASSACHUSETTS, A CORPORATION OF ELECTRIC MOTOR OR GENERATOR.

Patented Sept. 26, 1911.

To all whom it may concern:

Be it known that I, HERBERT A. BALCOME, a citizen of the United States,residing at West vRoxbury, Boston, in the county of Sufiolk and State ofMassachusetts, have invented certain new and useful Improvements inElectric Motors or Generators; and

I erated in the machine.

I do hereby declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilled in theart to which it appertains to make and use the same.

' The present invention relates to electric motors or generators, andmore particularly tothe coolin of the so-called adjustable speed types osuch machines which are designed to normally operate over a considerablerange of speed.

Itis common to artificially supply a cooling circulation of air to anelectric motor or generator to conduct away the heat gen- When a motoror enerator is designed to normally run at a airly constant speed, themeans for supplying the artificial cooling circulation of air ma beproportioned to supply a sufiicient clrculation to cool the machine atits normal speed. However, if the machine is designed to operate over aconsiderable range of speed certain difficulties are encountered withsuch artificial cooling.

. to cool it.

. a suflicient circulation o The moving parts of the machine, especiallyif hey be provided with a1r ducts,

tend of themselves to cause a circulation of I maintain it constant inamount, or prevent 1t from lncreasmg proportionally to the inair throughthe machine, so that in many cases when such a machine is running at itsif any, power need be expended by any other means to aid in the coolingcirculation of air. Hence at higher speeds the power used by a separateblowingmeans in inducing the circulation of air might be reduced andstill a suflicientthrough the machine circulation of air pass Moreover,when the blowlng means for causing the artificial circulation of air"is'driven by the motor or generator itself, the circulation of airartificially caused thereby will increase as the speed of the motororgenerator increases. Hence, if said blowing means be large enough tocause air to cool the motor or generator at lower speeds, the amount ofair delivered by said blowing means at the higher speeds will'be greatlyin excess of'the requirements for cooling,

lation of air than is required.

' Such relative decrease 1n expended by the blowing taming the totalcirculatlon of air maybe and the load imposed upon the blowing means tocause such an excessive circulation of a1r may amountto the greater partof the total load carried by the machine. It Is, therefore, imperativefor the economical operation of such machines that some means beemployed to relieve the blowing means from a part of the load imposedupon it in causing an artificial circulation of air when the motor orgenerator is running at its higher speeds.

W1th the above matters in view, the object of the present invention isto provide means acting automatically to restrict the clrculation of airthrough the motor or generator from exceeding the amount which isnecessary to cool it at the speed at which 1t is running, whereby theblowing means is relieved of having an unnecessary load imposed upon itin supplying a greater circu- The present invention 4 contemplatesbroadly the attainment of this object by any suitable means which willautomatically restrict the load imposed upon the blowing means inmaintaimng the circulation of air at difierent speeds of the motor orgenerator. Such means operates as the speed of the motor or generatorincreases, to restrict said load by decreasing, relatively to the speedof the motor or generator, the air delivery of said blowing means in anysuitable manner.

' the air delivery may actually reduce'the circulation of air,

crease in speed of the motor or generator. If the circulation of air isrestricted, the load imposed on ing the air circulation will likewise berestricted, and the blowing means relieved of doin unnecessary work.-The means for restricting the circulation of air may be so arrangedthat, if the moving parts of the machine do not materially contribute incausing the air to circulate, the power expended by the blowing means incausing the circulation of air may be kept approximately constant at allspeeds of the machine, or that, if the moving parts of the machine actas blowers to materially aid in causing the circulation of air, thepower means in mainthe machine inreduced as the speed of the blowingmeans 1n causcreases. Moreover, the means for restrictin thecirculation'of air may be so arrange that the volume of air per minutepassing through the machine at difi'erent speeds may be constant or maybe varied in amount to suit the different types of" machinesorconditions under which they are to be operated. The simplest and mostefficient manner of restricting the circulation of air supplied by theblowing means, is by throttling said flow or circulation of air.Themeans for throttling the circulation of aif preferably comprisesdampers or checks in the passages through which the air is forced.

In the drawing, the preferred embodiment of the invention isillustrated, the view showing aside elevation taken partly in section.

Referring to the drawing, the shaft 1 of a motor of generator; extendsthrough the end of the casing 2 of the machine; The casing is providedwith openings 3 through which the air is drawn to cause a coolingcirculation through the heated parts of the machine. Secured to anannular flange 4 on the casing within the region of these open-.

ings is a sheet metal drum 5 whose outer end is closed by a cap 6 inwhich is provided a bearing 7 for the shaft of the machine. Theperiphery of the drum 5 is provided with openings 8' at its outer end,and with other openings 9 nearer its middle. Secured to an annularflange 10 on the casing 2 outside of the region of the openings 3 isanother drum 11, the outer end of which is bent in to form a flange 12which extends to the drum 5 be,- tween its two sets of openings 8 and 9.An annularair passage is thus formed between the drums 5 and 11, and itis designed that the air shall circulate through it sis-indicated by thearrows, coming through the openings 3 in the motor or generator, passingthrough the openings 9 into the inner drum, and then escaping throughthe openings 8. This circulation of air is caused by a fan 13 mountedupon the shaft 1 directly inside of the openings 8. The circulation ofair caused by the fan 13 is restricted by a damper 14 which is designedto be moved to vary the areas of the air admission openings 9. Thedamper 14 comprises a drum-like rim 15 supported upon a hub 16 by aspider 17 which allows the passage of air longitudinally therethrough.The hub 16 is splined to slide longitudinally on the shaft 1, aboutwhich is coiled a helical compression spring 18 which normally holds thedamper in position to uncover the openings 9. The damper is moved toreduce the free areas of the openings 9 by the action of a wheel 19transversely pivoted at 20 to the shaft 1. When the shaft is rotated,the wheel 19 will tend to set itself at right angles to the shaft andwill. pull upon the link 21 which connects it to the hub- 16 of thedamper, and draw the.

damper along the shaft against the com ression of the spring 18. Theamount of lbrce tending to turn the wheel 19 will increase with thespeed of the machine, so that as the speed increases the damper will actmore the damper 14, the volume of air driven by tion of air is thusthrottled or restricted by the fan will not be increased unnecessarilywhen the machine is run at its high speeds, as would be the case if thecirculation were not restricted, and the fan will be relieved ofan.unnecessarily reat blowing load as the speed of the machineincreases.

The present invention is not limited to the specific embodiment asillustrated and described, but may be embodied in other forms within thespirit of the invention and the scope of the following claims: i

1. An electric motor or generator, having, in combination, means tosupply a cooling circulation of air thereto, an air passage for theconduction of said circulation of air, a damper in said air passagecontrolled by the speed of-the motor or generator to regulate thecirculation of air.

2. An electric motor or generator, having, in combination, means tosupply a cooling circulation of air thereto, an air passage for theconduction of said circulation of air, a damper in said air passage, andcentrifugally operated means controlled by the speed of the motor orgenerator to actuate said damper to regulate the circulation of air.

3. An electric motor or generator, having, in combination, means forsupplying a cooling circulation of air thereto, and means havingprovision for automatically decreasing, relatively to the speed of themotor or generator, the air delivery of said blowing means as the speedof the motor or generator increases.

4. An electric motor or generator, having,

in combination, means to supply a cooling circulation of air ther to,and means to automatically restrict the circulation of air as the speedof the motor or generator increases.

HERBERT A. BALCOME. Witnesses:

RoY T. WELLS, FRED. B. DOLAN.

